The invention relates as a whole to composite structures and may be used, in particular, in the manufacture of bodies or compartments of flying vehicles used in rocketry or aeronautics.
Stringent requirements are imposed upon composite shells shaped as a body of revolution in what concerns their strength and reliability, and the products must have a minimum weight. However, when the weight is reduced, the wall thickness decreases and there arises a danger of premature destruction of the product because of reduction of its strength. Therefore, in the composite shells shaped as a body of revolution, in the panels and in their connection joints are introduced various reinforcements.
Known in the art is a composite shell shaped as a body of revolution, comprising a load-bearing framework of a cellular structure consisting of crossing spiral and annular strips (U.S. Pat. No. 3,083,864, cl. 220-83, 1963).
Known in the art is another composite shell shaped as a body revolution, comprising a load-bearing framework of a cellular structure consisting of intersecting unidirectional fibers, and an outer load-bearing shell (U.S. Pat. No. 4,137,354, cl. 428-116, 1979).
In a composite shell shaped as a body of revolution (U.S. Pat. No. 4,284,679, cl. 428-218, 1981) comprising a load-bearing framework of a cellular structure, formed of layers repeating throughout the thickness of the wall and consisting of systems of crisscrossed spiral and annular strips, made of unidirectional fibers, forming stiffening ribs and cross nodes; and an outer load-bearing shell, between the strips are provided load-bearing interlayers. To improve stability of the ribs (U.S. Pat. No. 4,278,485, cl. 156-173, 1981) in the cells between the ribs are introduced foam plastic inserts having edge formers of a composite material.
Most close by its technical essence is a composite shell shaped as a body of revolution disclosed in U.S. Pat. No. 4,284,679 and chosen as the prototype, in which composite shell the intersecting spiral and annular strips are concentrated in cross nodes, that increases their structural depth and weakens relationship between the strips in the ribs, makes worse the quality and reliability of the structure, reduces the efficiency of its operation in the conditions of complicated stressed state.
Known in the art is a panel having a skin and strengthening elements in the form of ribs sagging towards the panel (USSR Inventor's Certification No. 1076691, F16S, 1/00, 1984).
It should be noted that such sagging is permissible as technological sagging, but not as structural sagging. Sagging results from technological shrinkage stresses, which are undesirable for the structure.
Known in the art is a composite panel comprising a load-bearing framework in the form of ribs, and a load-bearing shell covering said framework (USSR Inventor's Certificate No. 1046445, B32B 3/12, 1983).
In said panel structure is used complicated framing of the joint surfaces.
The most close analog, chosen as the prototype, is a composite panel disclosed in USSR Inventor's Certificate No. 1046445.
Known in the art is a joint connecting composite panels, said joint comprising their frameworks of a cellular structure formed of layers repeating throughout the thickness of their walls and consisting of systems of intersecting strips forming cross nodes and stiffening ribs therebetween, with outer load-bearing shells and connecting threaded rod elements (USSR Inventor's Certificate No. 1057651, F16S 1/02, 1983).
Known in the art is a number of connections, in which is not ensured reliable fixing of the panels in the joint.
In the composite panel connection joints (USSR Inventor's Certificate No. 458177, B64C 3/26, 1991) the filler is in the form of sheets changing beyond the joint into fibers. In the Russian Federation Pat. No. 532209, B64C 3/26, 1995, the panel structures are connected with the use of multi row combs, wherein the longitudinal rows are arranged at different angles for securing a reinforcing material.
In the USSR Inventor's Certificate No. 533004, F16B 5/02, 1981, structural members are connected by gaskets having cut-outs for more reliable securing of a reinforcing material.
The reinforcing elements of the joint may be made in the form of foil interlayers (USSR Inventor's Certificate No. 378611, F16B 5/02, 1983).
In a panel connection joint (EPO application No. 0019598, F16S 1/12, 1980) the flanges are joined in overlap by threaded elements.
The most close analog chosen as the prototype is a connection joint disclosed in Inventor's Certificate No. 1057651.